Since the release of our first LTS release, the community has been hard at work on the 2.4 version. I thought that 2.4 would be a transition release without much new features, but I was wrong, and many great changes have been made during the development phase. If you don't follow our day-to-day work, be sure to monitor this blog as I will write about the main new features in the coming weeks.
With 1000+ commits coming from 370+ pull requests, 2.4 is now feature freezed. The next two months will help us tweak the new features and finish the documentation.
This new version should be backward compatible with any projects based on 2.3,
so testing it should be as easy as bumping the Symfony version requirement in
composer.json file (for projects based on the Standard Edition, have
a look at the composer diff,
or the full changes done in the skeleton).
If you want to test it in isolation, create a new project via Composer:
$ php composer.phar create-project symfony/framework-standard-edition somewhere/ 2.4.0-BETA1
If you find any regressions or backward incompatible changes, please report them.